1. Field of the Invention
This invention relates to a driving tool, more particularly to a driving tool with a detachable telescopic retriever that can be extended to possess a relatively long length for retrieving a fastener disposed in a deep hole.
2. Description of the Related Art U.S. Pat. No. 5,878,637 discloses a driving tool having a tubular shank and a handle secured to one end of the shank for rotating the same. The shank has another end formed with an engaging opening adapted for receiving a tool bit. A telescopic retriever is received in the shank, and has one end secured to the handle and the other end provided with a magnet member that is adapted to attract the tool bit for retaining the tool bit at the engaging opening. The telescopic retriever can be extended to allow extension of the magnet member outward of the shank to reach a fastener disposed in a deep hole.
However, the above-described driving tool is found to have the following drawbacks:
1. Since a tool bit is to be retained in the engaging opening of the shank, the axial bore of the shank is typically designed to have a diameter smaller than that of the engaging opening. As the telescopic retriever extends into the shank, the diameter of an outermost tube member of the telescopic retriever must be smaller than the cross-section of the axial bore of the shank. Therefore, the entire length of the telescopic retriever after extension is severely limited.
2. Because the telescopic retriever is secured to the handle, the telescopic retriever cannot be detached from the driving tool for individual use.
3. Since the tool bit is retained on the shank by the magnet member, when the tool bit is used for driving a fastener mounted on a magnetically sensitive object, such as an electronic component of a computer, the magnetic field generated by the magnet member can damage the electronic component.